How & Why of living on less than 87 liters of water!

It may be raining and our gardens are looking green again but our water situation is still deep in the red.  Unless we are far more frugal with the water we have right now, predictions by weather and water specialists show a very high probability that Cape Town will run out of water by early March 2018.   How can that be?  Look at the calculations below based on current water consumption levels. (source: weather scientist, Dr Peter Johnston, UCT who admits to being cautiously conservative. Quite right too considering what is at stake.)

2017 08 water drop Q your score (5)Dam Levels as of 14 August = 31.0%   (Net amount of extractable water 21.0%)

Predicted Winter rain weekly dam level increase of 0.5-2% (say 1.5%)
Predicted Summer weekly consumption drop of 0.5-1.5% (say 1%)
Weeks remaining this Winter assuming winter rain over by spring equinox, Sept 23 = 5 weeks. Likely total dam level increase owing to winter rain:  7.5%
Usable level by Mid September 28.5% (31+7.5 less 10% )
Summer weekly consumption & evaporation drop of 1% = 28.5 weeks = 200 days
Water runs out in 200 days from 14 August on 2 March!! NO EXTRACTABLE DAM WATER! See graph comparing dam levels and water consumption at the end of the article.

Collectively we are using 630 million litres of water each day while the City’s target is 500 million litres or 87 litres per person. 87 litres of water per person for household consumption is entirely doable. The best opportunity we have to make the meagre supply last is to save as much of what we have starting from NOW.  The City has a number of expensive emergency interventions including desalination, boreholes into deep aquifers and trucking in water (from where?). The city’s intent is to drive down collective usage to 500 Mℓ/day as well as to ensure that there is always at least 500 Mℓ/day of water in production. ( big question is how likely, given the scale of the operations, will sufficient water augmentation be implemented in time?

We can’t wait for the City to manage this crisis so that we don’t run out of drinking water.  The inconvenient truth is that everyone can and needs to reduce consumption to below 87 liters starting now.  Many are already using less – more need to do so!  Based on the increasing cost of water to pay for the City’s augmentation projects, it also makes financial sense to be as water efficient as possible.

Every drop counts!  How do you measure up against the official target of 87litres per day?  Look at the Water Budget Table below based on using 87 litres in the left hand columns and see how much more you can save with the tips in the right hand columns.

87 Litre target Activity   How you can do better! Less litres
2 Reserve 2 litres in a bucket for hand washing Use to flush toilet at end of day. 2
0.5 For brushing teeth For brushing teeth 0.5
35 A two minute shower can use as much as 30 – 40 litres.

Catch shower water in a basin to use for flushing the toilet.

Reduce water pressure while showering. Switch off flow while soaping. Catch shower water in a basin. It is not necessary to shower every day. Wash in a basin and only use 5 – 10 litres of water. 10 -20
30 A toilet flushes between 9 – 10 litres. Three flushes per day uses 30 litres of drinking water. Flush a maximum of 2 x per person per day, preferably using shower, rain or well point water. Reduce volume of cistern by placing a 1 – 2 litre bottle in it. 16
4 Water for drinking and cooking. Water for drinking and cooking. Cook with family and friends to save water. 4
5.5 Washing dishes. Wipe scraps off the plates to reduce need for water. Wash dishes once a day. Wipe scraps off the plates to reduce need for water. Rinse washed dishes in basin and reuse this water. 4.5
6 Washing clothes 2 x per week uses about 36 litres 6 litres per day. Washing clothes 2 x per week uses about 36 litres or 6 litres per day. Use bio-friendly detergent and catch rinse water to reuse for washing floors or watering plants. 6
6 Use shower water or clothes rinse water to wash floors. Use shower water or clothes rinse water to wash floors. 6
Total 88 litres minus re-use of 30 litres of shower and 6 litres of clothes rinse water = 52 Litres of drinking water used.   50 – 60 litres minus re-use of 10 – 20 litres of shower and 6 litres of clothes rinse water = 34 – 44 Litres of drinking water used per day.

We are not the only citizens in Cape Town impacted by the drought. As summer approaches please remember the birds, lizards, frogs and urban wildlife and top up the bird baths and dishes of water for the ground dwellers.


Kim Kruyshaar 2017 08 20

2017 08 Daily Mavrick rain & dam levels graph of past 6 years


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16 Responses to How & Why of living on less than 87 liters of water!

  1. Karen Gray-Kilfoil August 21, 2017 at 1:09 pm #

    Great article, with nice new ideas to try out. We have a jug of rain/wellpoint water next to the kitchen sink that we use for washing/rinsing dishes and fruit/veg. Sharing meals is a great way to save cooking water. Microwaving uses less water than boiling…. Karen

  2. Kathryn Kruyshaar August 21, 2017 at 2:39 pm #

    Thank you for an excellent article. I will read this to the Somerset College Sustainability Committee on Wednesday as it is practical and helpful. As a school, we are very concerned as well as aware that we need to use less water while retaining standards of hygiene.

  3. Alice Ashwell August 21, 2017 at 3:51 pm #

    Brilliant article Kim. You are right to remind us that the predictions regarding dam levels are dire. It’s easy to slack off when there’s green all around us, but there’s a long summer coming and the cost of exploiting alternative water sources is going to be huge. Our drums and buckets are full, thanks to the rain, and our loos are full of rather green water from Zandvlei! Your table is a great reminder of just how lightly we can tread – thank you for your clarity and commitment.

    • admin August 21, 2017 at 4:24 pm #

      Lucky that you can go Zandvlei Green while many of us have mellow yellow. And it is important to remember that our water borne sewage system does need water – preferably not drinking water.

  4. Sarah August 21, 2017 at 5:52 pm #

    Thanks for drawing up this table Kim. It offers clarity and inspiration. We’ve had problems with our sewer clogging up because of not flushing enough water through our toilet. This has been motivation to find even more ways of recycling water through our toilet cistern, collecting from hot water bottles, shower, hand washing basin, from cooking pots after boiling eggs… While we use the very short quick cycle on our eco washing machine, I’m struggling to reduce the number of weekly loads, especially with all the layers of clothes we wear in winter and bedding to change for Bnb guests! While we’ve been collecting shower water with a bucket, it looks like it’s time to reduce the number of showers per week though.

    Why do I share all this? Because it’s encouraging to know that there are more people out there doing the same… It’s been so heartening to me to come into people’s homes and to find we’re united and going through the same motions. Thanks everyone and keep going. 🙂

  5. Evanne Rothwell August 21, 2017 at 6:17 pm #

    Run water into a bottle while waiting for the hot water to come through the taps. We get almost enough water for drinking this way.

  6. Liesbet Joubert August 22, 2017 at 5:24 am #

    Thanks Kim for practical article and sound advise. I will share it with my colleagues and pupils. So happy about overnight rain, but I know we need more to advert crisis this summer.

  7. Margot Roebert August 22, 2017 at 8:39 am #

    Kim, thank you for this fabulous article. Brian has printed it off for the men who work for him and I am about to read it to the girls. I have also shared it with the staff. Together we can make a difference. Thank you always for the reminder!

  8. Lindsey Macdonald August 22, 2017 at 8:59 am #

    We collect the cold water from the shower (before it runs hot) and use that to flush the toilet.

  9. Ros Irlam August 22, 2017 at 10:08 am #

    Thank you for a helpful article. It would be good to add how many litres are used per person by using a dishwasher once a day, as this is how many of us wash dishes.

    Our tip: We all shower once or twice a week. For the other days, we use a two litre tub and fill it three quarters full (i.e. 1.5 litres). We find this is enough to have a good wash. And then it is used in the cistern.

    • admin August 22, 2017 at 12:00 pm #

      I find it wonderful how many people have commented that they have reduced showering and use minimal water to wash on non- shower days. We do the same but are not as efficient as your 2 liter wash. Does anyone know what the minimum water requirement is to keep our sewers flowing and not a health hazard? I shall try and get an answer from the city? Your dish washer water will go into the sewer – so you should not get blocked!!! Re the dish washer vs washing in the sink, it varies so much depending on the model and the setting you run it on. Sorry I can’t give a definitive answer. BUT: Advantage of the sink IF people practice water wise washing is that you can re-use your rinse water if you rinse in a basin. Also if you scrape or wipe the plates before washing then you need less washing water. So is your dishwasher a modern water efficient one and when you do use it do you make sure it is a full load? Some people rinse their dishes before loading the dishwasher – that is the least water wise option. If your dish washer needs pots or dishes to be pre-rinsed then rather hibernate it till our water crisis is over. Or invest in a truly water wise one. We don’t use our dishwasher at the moment.

  10. Mariette August 22, 2017 at 4:12 pm #

    I’d love to load this on my FB page – what’s the easiest way to do it?

    • admin August 22, 2017 at 5:44 pm #

      You can just copy and paste the link. thanks for helping to spread the awareness.

  11. Sandra van Rensburg August 22, 2017 at 8:37 pm #

    Thank you for a very insightful and helpful article. I live in a flat and use all my washing machine water (stored in every container possible) for my toilet. We are two in the flat and flushes the minimum. Also used already stored water for cleaning the house purposes.

    The biggest lesson for me is that I have realised how much water we are actually wasting every day and will continue to use more of the good ideas given hear.

  12. Paul August 28, 2017 at 3:46 pm #

    Many thanks for the great information. We are now averaging 100l/day for the two of us. The graph is frightening. We will have to work out how to treat our well point water for household use!

    • admin August 29, 2017 at 11:13 pm #

      hi Paul, We are using our rainwater supplemented by well point to flush the toilet as our showers are so short they don’t generate enough water. I am also using rain or well water to wash dishes which requires boiling water in the kettle rather than using our solar geyser. A wake-up about the strong connection between energy and water. I now also pre soak clothing in rain/well water to reduce the water used in the washing machine. But still drinking and cooking with city water.

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